Hydraulic slicing machine control



Oct. 7, 1969 D. DOHM, JR

HYDRAULIC SLICING MACHINE CONTROL 2 Sheets-Sheet 1 Filed Jan. 30, 1967 Oct. 7, 1969 D. DOHM, JR

HYDRAULIC SLICING MACHINE CONTROL I 2 Sheets-Sheet 2 Filed Jan. 30, 1967 I United States Patent 3,470,926 HYDRAULIC SLICING MACHINE CONTROL Daniel Dohm, Jr., University City, Mo., assignor to Dohm and Nellie, Incorporated, St. Louis, Mo., a corporation of Missouri Filed Jan. 30, 1967, Ser. No. 612,390 Int. Cl. A22c 17/02 US. Cl. 146-95 'Claims ABSTRACT OF THE DISCLOSURE A slicing machine, particularly for slicing slabs of bacon, having a carriage moved by a hydraulic cylinder for feeding a slab of bacon toward a rotating knife, the

hydraulic circuit including a pump and a reversing valve for eflecting rapid return of the carriage. The reversing valve bypasses the hydraulic circuit and valves normally employed for forward carriage travel and connects the hydraulic pump directly to the forward end of a hydraulic cylinder connected to the carriage.

Background of the invention The invention pertains to slicing machines, and particularly to a hydraulic control for rapid return of a slicing machine carriage.

A conventional type of bacon-slicing machine comprises a reciprocating carriage for gripping a slab of bacon to be sliced and advancing the slab toward a rotating slicing blade. A hydraulic ram or cylinder is provided for moving the carriage toward the blade until the bacon is completely sliced and then for returning the carriage to a loading position for insertion of another slab to be sliced. Although such machines are capable of slicing large quantities of bacon in a short time, some productive time is wasted by the relatively slow return of the carriage to its loading position. This slow return is caused by the inherent design of the machine in that the hydraulic circuit which provides operating fluid to the hydraulic ram for forward carriage motion also provides operating fluid for return carriage motion. Since the capacity of the hydraulic circuit is determined by the maximum forward speed of the carriage and this is limited by the slicing rate of the blade, the return speed of the carriage is similarly limited because of the common hydraulic circuit. Additionally, the friction produced by the fluid passing through the hydraulic circuit further reduces the return speed of the carriage since a portion of its energy is liberated to the ambient as waste heat.

Summary of the invention Accordingly, the present slicing machine provides an improved hydraulic circuit for increasing the speed at which the carriage returns, thus attaining the object of increasing production by decreasing nonproductive carriage return time.

The present slicing machine is comprised of a slicing blade rotatable on a shaft, a reciprocating carriage for feeding a product to be sliced to the blade, and hydraulic means for moving the carriage. The hydraulic means consists of a double-acting hydraulic cylinder having a piston connected to the carriage and fluid lines connected to the rearward and forward ends of the cylinder for reciprocating the carriage. A hydraulic circuit including a plurality of valves is provided between a fluid pump and the cylinder for normally directing the fluid to the cylinders rearward end. In addition, means are provided for bypassing the hydraulic circuit and valves and for connecting the pump directly to the forward end of the cylinder to reverse the direction of carriage movement and avoid the limited capacity and friction in the hydraulic 3,470,926 Patented Oct. 7, 1969 "ice circuit. Other objects and features will be in part apparent and in part pointed out hereinafter.

Brief description of the drawings Description of the preferred embodiment Referring to FIGS. 1 and 2, there is shown a slicing machine, generally indicated by numeral 1, comprising a table 3 supported by legs 5. On the top of the table 3 is a bed 7 having an upstanding blade housing 9 at one end and a drive housing 11 at the other end. An electric motor 13 is mounted on the bed 7 for driving a shaft 15 20 ,through a pulley and belt mechanism 17 disposed within the housing 11. A rotatable slicing blade 19 in housing 9 is secured to the other end of the shaft 13 for rotation by motor 15. A hydraulic pump 21 driven by motor 15 supplies hydraulic fluid, under pressure, to a hydraulic circuit 22 (see FIG. 3) for reciprocating a carriage 23 along a guide surface 24, the carriage having fingers 25 for gripping a slab of bacon indicated at 26.

The hydraulic circuit for reciprocating the carriage is illustrated in FIG. 3. Generally, the hydraulic pump 21 supplies hydraulic fluid to a reversing valve 27, a manually operable on-off valve 29, a rapid traverse valve 31, a metering valve 33, a trip valve 35, and thence to a double-acting hydraulic ram or cylinder 37 having a piston rod 39 connected (by a linkage not shown) to the carriage 23.

More particularly, the hydraulic pump 21 has an inlet 41 connected by a fluid line 43 to a hydraulic sump or reservoir. A pressure relief valve 44 having a line 46 to sump is connected to the pump 21 for controlling its discharge pressure. The pump outlet 45 is connected to inlet 47 of the reversing valve 27, the latter having a first outlet 49 connected by a line 51 to the forward end 52 of the cylinder 37, a second outlet 53, an actuator (not shown), an actuator inlet port 55, and a sump return port 57. a

The second outlet 53 of the reversing valve 27 is connected via line 59 to inlet 61 of the on-off valve 29. The valve 29 has an outlet 63 and a manually operable knob 65 for connecting its inlet 61 to its outlet 63, the latter being connected by a line 67 to an inlet 69 of the rapid traverse valve 31.

Valve 31 has a first outlet 71 connected by line 73 to the rearward end 74 of the cylinder 37 and a second outlet 75 connected to the sump. A return port 77 is connected to both the forward end 52 of the cylinder byline 78 and to the metering valve 33. A manually operable lever 79 is associated with the valve 31 through a linkage 81 for operating valve 31 to connect port 77 to outlet 75, and a fluid operable actuator 83 is provided for operating valve 31 to connect port 71 to outlet 75.

The metering valve 33 is connected at inlet 85 to return port 77 of the rapid traverse valve 31 by a line 86. The valve 33 has an outlet 87 to sump and a control knob 89 for varying the flow rate from its inlet 85 to its outlet 87.

The trip valve 35 is of the rotary type having an inlet 91 connected via line 93 to inlet 69 of valve 31, and an outlet 95 connected by lines 97 and 99 respectively to the rapid traverse valve actuator 83 and reversing valve actuator inlet port 55. The trip valve 35 is provided with an actuator 101 connected by a suitable linkage (not shown) to the carriage 23 for actuation as the carriage reaches the end of its forward and return strokes. The valves 35 and 29 are returned to the sump through lines 103 and 105, respectively.

In operation, a slab of bacon 26 is placed on the guide 24 and attached to the fingers 25 of carriage 23. The motor 15 is energized causing the blade 19 to rotate and the pump 21 to force hydraulic fluid from the sump to the reversing valve 27. Since the actuator of valve 27 normally covers its first outlet port 49 and uncovers its second outlet port 53 (the actuator may be spring biased to this position), hydraulic fluid is caused to flow through line 59 to the on-off valve inlet 61. To start forward carriage movement, the knob 65 is operated to connect its inlet 61 to its outlet 63 and permit the hydraulic fluid to flow to the rapid traverse and trip valve inlets 69 and 91. In the normal position of the rapid traverse valve actuators, the inlet port 69 is connected to the outlet port 71 for providing fluid through line 73 to the rearward cylinder end 74. This forces the piston and piston rod 39 forward and moves the carriage 23 toward the slicing blade 19. As the piston moves forward, hydraulic fluid is forced out the forward cylinder end 52 through lines 78 and 86 and into the inlet 85 of the metering valve 33. The rate of forward movement of the piston rod 39 and carriage 23 may therefore be controlled by adjustment of the control knob 89 of the metering valve.

When the carriage 23 reaches the forward end of its stroke and the bacon 25 is completely sliced, the linkage connecting the carriage and trip valve actuator 101 causes the latter to rotate and connect its inlet 91 to its outlet 95 to provide pressurized hydraulic fluid through lines 97 and 99 to the rapid traverse valve actuator 83 and the reversing valve actuator inlet port 55. The actuator 83 connects the rapid traverse valve port 71 to the sump through outlet port 75 and causes the reversing valve actuator to cover port 53 and uncover port 49. Since port 53 is covered, the flow of hydraulic fluid through hydraulic circuit 22 and valves 29, 31, 33 and 35 is interrupted and the full quantity of fluid from pump 21 is delivered to the forward end 52 of the cylinder 37 through line 51. The piston in the cylinder 37 therefore begins its rearward travel forcing the hydraulic fluid out the line 73 and through ports 71 and 75 to the sump. Upon completion of the return stroke, the actuator 101 of trip valve 35 is again operated by the carriage 23 to interrupt the flow of fluid through lines 97 and 99 and permit the reversing valve actuator to return to its normal position wherein port 53 is uncovered and port 49 covered. Thus, the fluid is again permitted to flow through the hydraulic circuit 22 and into the rearward end 74 of the cylinder 37 for moving the carriage and another slab of bacon secured thereto toward the slicing blade 19.

The rapid traverse lever 79 is utilized to decrease nonproductive forward travel time when a short slab of bacon is to be sliced. That is, when a short slab of bacon is secured to the carriage 23, the lever 79 is operated to connect return port 77 to the sump through outlet 75 and permit some of the fluid from the forward cylinder end 52 to return directly to the sump through the rapid traverse valve 31, thus increasing the forward speed of the piston rod 39 and carriage 23 for more rapidly advancing the short slab toward the blade 19.

It is thus seen that the present invention increases the return speed of the carriage 23 by by-passing the hydraulic circuit 22 and valves 29, 31, 33 and 35 to permit the full volume of fluid from the pump 21 to flow to the forward cylinder end 52. Therefore, the resistance to flow through the hydraulic circuit and valves is eliminated and the carriage more rapidly returns to its loading position to increase production of the machine.

In view of the above, it will be seen that the several objects of the invention are achieved and other advantageous results attained.

As various changes could be made in the above constructions without departing from the scope of the invention, it is intended that all matter contained in the above description shall be interpreted as illustrative and not in a limiting sense.

What is claimed is:

1. A slicing machine having a slicing blade rotatable on a shaft, a carriage for feeding a product to be sliced to the blade, and hydraulic means for moving the carriage, said hydraulic means comprising:

a double-acting hydraulic cylinder having a piston connected to the carriage and fluid lines connected respectively to the rearward and forward ends of said cylinder for reciprocating the piston and carriage; hydraulic fluid sump;

:a pump having an inlet connected to the sump and an outlet;

a reversing valve having an inlet connected to the pump outlet, a first outlet connected to the forward end of the cylinder, a second outlet, and means for connecting its inlet to either of its outlets;

a manually operable on-off valve having an inlet con nected to the second outlet of the reversing valve, :and an outlet;

a rapid traverse valve having an inlet connected to the on-olf valve outlet, a first outlet connected to the rearward end of the cylinder, a second outlet connected to the sump, a return port connected to the forward end of the cylinder, a first actuator for connecting its return port to its second outlet, and a second actuator for connecting its first to its second outlet;

a metering valve having an inlet connected to the forward end of the cylinder. and an outlet to the sump;

and a trip valve having an actuator operable by the carriage at the end of its forward stroke for operating the reversing valve to disconnect its inlet and second outlet and connect its inlet and first outlet, thereby bypassing the on-ofl, rapid traverse, metering and trip valves and connecting the pump directly to the forward end of the cylinder for reversing the carriage.

2. A slicing machine as in claim 1 wherein said means for connecting the reversing valve inlet to either of its outlets comprises a fluid operable actuator having an actuator inlet port.

3. A slicing machine as in claim 2 wherein said trip valve has an inlet connected to the on-off valve outlet, and an outlet connected to the reversing valve actuator inlet port.

4. A slicing machine as in claim 3 wherein the second actuator of the rapid traverse valve is fluid operable and is connected to said trip valve outlet for simultaneous actuation with the reversing valve actuator.

5. A slicing machine having a slicing blade rotatable on a shaft, a carriage for feeding a product to be sliced to the blade, and hydraulic means for moving the carriage, said hydraulic means comprising:

a double-acting hydraulic cylinder having a piston connected to the carriage and fluid lines connected respectively to the rearward and forward ends of said cylinder for reciprocating the piston and carriage;

a hydraulic fluid sump;

a pump having an inlet connected to the sump and an outlet;

a reversing valve having an inlet connected to the pump outlet, a first outlet connected directly to the for- Ward end of the cylinder, a second outlet, and an actuator for connecting its inlet to either of its outlets;

a manually operable on-off valve having an inlet connected to the second outlet of the reversing valve, and an outlet;

a rapid traverse valve having an inlet connected to the on-off valve outlet, a first outlet connected to the rearward end of the cylinder, a second outlet connected to the sump, a return port connected to the forward end of the cylinder, a manually operable actuator for connecting its return port to its second outlet, and a fluid operable actuator for connecting its first to its second outlet;

6 valve causes said reversing valve actuator to disconnect its inlet and second outlet and connect its inlet and first outlet for bypassing the on-off, rapid traverse, metering and trip valves and connecting 5 the pump directly to the forward end of the cylinder a metering valve having an inlet connected to the rapid for reversing the carriage.

traverse valve return port, and an outlet to the sump; and a trip valve having an inlet connected to the rapid traverse valve inlet, an outlet connected to the re- References Cited UNITED STATES PATENTS versing valve actuator and the rapid traverse fluid 10 2,642,910 6/1953 Garapolo 146 95 operable actuator, and an actuator operable by the 2,922,280 1/1960 Rehlander 60 51 carriage as the latter approaches the end of its for- 3,338,283 8/1967 Harms et ward stroke towards said blade for connecting its inlet to its outlet, whereby actuation of said trip W. GRAYDON ABERCROMBIE, Primary Examiner 

